Concentration of minerals



Patented Dec. 15, 1936 UNITED STATES PATENT OFFICE v 2,064,031 CONCENTRATION or MINERALS Oliver 0. Ralston, Clarkdale, Aria, assignor, by

mesne assignments, to Phelps Dodge Corporagonl1 New York, N. Y., a corporation of New No Drawing. Application October 6, 1930, Serial No. 486,746

p 10 Claims. (01.209-167) This invention relates to the concentration of 1y low percentages of solids, by weight, may be minerals and has for an object the provision of employed. an improved process for concentrating minerals The following table illustrates the results obby froth flotation. More particularly, the intained in treating reground rougher zinc con- 5 vention contemplates the provision of an imcentrates obtained by treating United Verde 5 proved method for controlling the extraction of mine ore in which zinc is present in the form of valuable minerals and grade of concentrate prcmarmatite:-

duced.

In froth flotation processes it is customary to Cleawmd Concentrates Extraction conduct one flotation operation for the purpose percent solids percent Zn (percent) 10 of obtaining a rougher concentrate and then subject the rougher concentrate to a second flo- 10 31.5 76.5 tation operation for the purpose of obtaining a 20 21.5 82.5 concentrate containing a higher percentage of i3 3 g;

the valuable mineral, the tailings from the sec- 45 81-5 84.8 15 0nd operation being mixed with the feed treat- 2; 33;;

ed during the first operation.

The tailings from the first or rougher operation may be wasted, so it is important that the g gp i g t operation be so conducted that maximum exp p ensl y an mam amlpg .er con 2o traction be accomplished Since the rougher nous constant The cleaner cucmt was operconcentrates are'retreated, grade of concentrate atmg on reground rougher concentrate ing about 16% Zn. The cleaner tailings were $12 k; 1x352; ggg z g g ggg g 'retumed continuously to the head of the rougher 0nd or cleaner 0 eration are retreated in the circuit rougher operatic; so extraction may be sac- T results.obtained Show t clean-er ope!" 25 rificed in favor of grade of concentrate in the atlons employmg pulps contain-mg about ten cleaner Operation cent or less of solids produce concentrates cor- I have discovered that improved results may responding grade to those produced h ho obtained by controlling the densities of the Pulps cmmmmg abut pement. pulps employed in the rougher and cleaner opare employed extmfctlon however 18 beterations. I have found that grade of concenter when the hlgher density pulps amused f trate obtained improves and extraction becomes therefore t to employ such pulps poorer as pulp density increases. I, therefore, cleaner opera 1on5 propose to employ a pulp of relatively low A complete process of the invention for treatsity in conducting the rougher operation and a i an ore of E type of Umted verdfmme ore 35 pulp of relatively high density in conducting the involves grinding of the ore to a suitable parcleaner operation. I have discovered that imtime Size, f' f of the ground Product In 3 proved extractions and improved grades of con- Pulp wqtammg more than aboufi forty 40 centrates are obtained when pulps containing cent solids with the addition of suitable flota- 0 not more than about forty percent, solids, by Q agfmts p & ce trate, weight are employed in the rougher operation 0f the rougher concentrate to Obtaln and when pulps of greater densities than the p a u cQntaimng 110M955 thanwabout forty P pulps employed in the rougher operations are n d t tfea'tment 0f the thickened p p 5 employed in the cleaner operations. I have also with the flddltion of suitable flotation agents discovered that improved grades of concentrates to Produce a cleaner concentrate d a Cleaner may be obtained by regrinding the rougher contailing, i return the cleaner a ng to the centrates before subjecting them to the cleaner rougher 0111311111- operation, The rougher concentrate may be reground be- The relative pulp densities employed in the being bjected to the cleaner operation.

rougher and cleaner operations in the treatment Regrinding is preferably conducted after the of any particular ore will be determined by the rougher concentrate pulp has been thickened. natures of the minerals in the'ore. In treat- Thickening or dewatering of the rougher coning ores containing minerals having relatively centrate may be conducted in any suitable manlow specific gravities, pulps containing relativener. 55

I claim:

1. The method of concentrating minerals which comprises subjecting the mineral in a relatively low-density pulp to a froth flotation operation to produce a rougherco'ncentrate, the density of the pulp employed in the production of the rougher concentrate being such as to provide for optimum recovery of valuable mineral, and subjecting the rougher concentrate to a froth flotation operation in a relatively higher density pulp, the density of the pulp employed in treating the rougher concentrate being such as to provide for the production of a concentrate of optimum quality.

2. The" method of concentrating minerals, which comprises subjecting the mineral in the form of a relatively low density pulp to a froth flotation operation to produce a rougher concentrate, forming a high density pulp of the rougher concentrate, and subjecting the resulting pulp to a second froth flotation operation, the pulp treated in said second froth flotation operation being of a substantially-higher density than the'pulp employed in forming the rougher concentrate.

3. The method of concentrating minerals, which comprises subjecting the mineral to a froth flotation operation in a relativelyv low density'pulp to produce a rougher concentrate, grinding the rougher concentrate, forming a pulp of the rougher concentrate ofsubstantially higher density than that employed in obtaining the rougher concentrate, and subjecting the resulting pulp to a second froth flotation operation.

4. The method of treating sulphide ores, which comprises subjecting the ore in the form of a pulp to a froth flotation operation to produce a rougher concentrate, forming a pulp of the rougher concentrate of substantially higher density than that employed in obtaining the rougher concentrate and containing not less than about forty percent solids, and subjecting the resulting pulp to a second froth flotation operation.

5. The method of treating sulphide ores; which comprises subjecting the ore in the form of a pulp to a froth flotation operation to 0btain a rougher concentrate, grinding the rougher concentrate, forming a pulp of the rougher concentrate of substantially higher density than that employed in obtaining the rougher concentrate and containing not less than about forty percent solids, and subjecting the resulting pulp to a second froth flotation operation.

6. The method of treating sulphide ores,

7. The method of treating sulphide ores,j

which comprises subjecting the ore in the form of a low density pulp containing not more' than about forty percent. solids to a froth flotation operation to produce a rougher concentrate,

grinding the rougher concentrate, forming a high I density pulp of the rougher concentrate, and

subjecting the resulting pulp to a second froth flotation operation, the pulp treated in said second froth flotation operation being of a substantially higher density than the pulp employed in forming the rougher concentrate.

a. The method of treating sulphide ores, which comprises subjecting the ore in the form of a low density pulp containing not more than about forty percent. solids to a froth flotation operation to produce a rougher concentrate, dewatering the rougher concentrate to produce a pulp of substantially higher density than that employed in obtaining the rougher concentrate, subjecting the concentrates in the higher density pulp to a grinding operation, and subjecting the resulting pulp to a froth flotation operation.

9. The method of treating sulphide ores, which comprises subjecting the ore in the form, of a low density pulp containing not more than about forty percent. solids to a froth flotation operation to produce a rougher concentrate, subjecting the rougher concentrate to a wet grinding operation,

dewatering the resulting pulp to produce a pulp of substantially higher density than that employed in obtaining the rougherconcentrate, and subjecting the higher density pulp to a froth flotation operation.

10. The method of treating sulphide ores, which comprises subjecting the ore in the form of a low density pulp containing not more than about forty percent. solids to a froth flotation operation to produce a rougher concentrate, forming a high density pulp of the'rougher concentrate, and subjectingthe resulting pulp to a second froth flotation operation, the pulp treated in said second froth flotation operation being of a substantially higher density than the pulp employed in forming the rougher concentrate.

' OLIVER C. RALSTON. 

